Principles of Plant Breeding (2+1)

Hardy-Weinberg law

• This law is independently developed by Hardy (1908) in England and Weinberg (1909) in Germany. The law states that the gene and genotype frequencies in a mendalian population remain constant from generation after generation if there is no selection, mutation, migration or random drift.
• The frequencies of thethese genotypes for a locus with two alleles A and a would be P²(AA), 2pq(Aa)and q²(aa)

             Where, p= Frequency of ‘A’ allele in the population.
• q= Corresponding frequency ‘a’ allele in the population the sum of p+q is equal=1 Such a population would be at equilibrium since the genotypic frequencies would be stable, that is, would not change from one generation to the next.This equilibrium is known as Hardy Weinberg equilibrium.